Hydraulic shock absorber and the like damping means



Dec. 5, 1939. F. G. G. ARMSTRONG 2,182,272

HYDRAULIC SHOCK ABSORBER AND THE LIKE DAMPING MEANS Original Filed May 23, 1938 2 Sheets-Sheet l 1 Ill/1 Dec. 5, 1939 F. e. s. ARMSTRONG HYDRAULIC SHOCK ABSORBER AND THE LIKE DAMPING'MEANS Original Filed May 23, 1938 2 Sheets-Sheei 2 Inventor I by M Y A ttorn eyS Patented Dec. 5, 1939 UNITED STATES HYDRAULIC SHOCK ABSORBER AND THE LIKE DAMPING MEANS Fullerton George Gordon Armstrong, Beverley, England Original application May 23, 1938, Serial No.

209,623. Divided and this application January 25, 1939, Serial No. 252,828.

ain December 31, 1936 8 Claims.

The present invention relates to hydraulic shock absorbers and the like differential pressure operated damping means of the type wherein a resistance to relative displacement between two elements such as, for example, a vehicle body and a wheel axle, is effected by resisting fluid flow between a pair of piston chambers in the shock absorber or the like damping means constituted by separate cylinders in each of which a piston is displaceable.

According to the present invention the chambers are hydraulically interconnected by three conduits, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, such as horizontal, and the others are available to fluid flow according to the direction of tilt or tendency to tilt of one element relatively to the other.

In one construction according to the present invention the chambers are hydraulically interconnected by three conduits, one of which only is available for fluid flow when one of the two elements whose relative displacement is to be damped lies horizontal and the other two of which are separately available to fluid flow ac-- cording to that direction in which said element tilts or tends to tilt from the horizontal position, that is to say, when the element tilts or tends to tilt in one direction the second conduit only is available to fluid flow, whilst in the opposite direction the third conduit is available to fluid flow.

Further by the present invention a differential resistance is available to fluid flow in each of the conduits considered separately, that is to say, resistance to fluid flow in one direction along each conduit may be different from the resistance to flow in the opposite direction along the same conduit.

Where the hydraulic shock absorber or the like differential pressure operated damping means of the present invention is utilised for damping relative displacement of a vehicle body with a wheel axle, it will thus be seen that no matter whether the vehicle is travelling with the chassis horizontal or is cornering in either direction with the chassis tilted or tending to tilt under the action of centrifugal force, a greater resistance to fluid flow may be available in one direction between the piston chambers than in the other, thereby offering considerable resistance to tilting and a smaller resistance to fluid flow caused by the vehicle meeting an obstruction in the road while cornering.

In Great Brit- A further feature of the present invention resides in the provision on a vehicle of pendulum or inertia mass means adapted for displacement under the action of centrifugal force or on tilting of the element on which said means is mounted, so as to isolate two of the conduits at a time, thereby leaving one conduit only available for fluid flow between the piston chambers, said inertia mass means being common to all damping means on the vehicle and being mounted in a position remote from each, preferably centrally of the vehicle chassis.

The pendulum, inertia mass or the like means may operate a spindle having three spaced transverse bores therein which spindle is longitudinally displaced by the pendulum or inertia mass means according to the position of the latter, transversely across the three conduits, the spacing of the bores in the spindle being such that only one bore synchronises with the conduit at any time.

The invention is more particularly described with reference to the accompanying drawings, in

which:-

Figure 1 is a vertical section through a shock absorber of that type to which the present invention is applied.

Figure 2 is a longitudinal section through part of the shock absorber of Figure 1 showing the relative positions between the cylinders and the spindles for controlling the conduits between said cylinders.

Figure 3 is a diagrammatic vertical section through the lower part of a shock absorber showing one form of construction of the present invention applied thereto, and wherein a setting spindle is adapted for angular rotation about its axis to control the conduits between the cylinders.

Figure 4 is a diagrammatic view of a suitable form of mechanism for effecting angular rotation of the setting spindle of the construction according to Figure 3.

Figure'5 is a vertical section through a modified form of shock wherein the setting spindle is displacedlongitudinally to effect control of the conduits between the shock absorber cylinders.

Figure 6 is a diagrammatic section through a shock absorber similar to that of Figure 4, but showing a modified form of construction for operating the setting spindle.

Figure 7 is a diagrammatic view showing the mounting of the parts of the shock absorber on the displaceable elements.

In considering the drawings it should be ap- 55 preciated that the present invention is not disclosed in Figures 1 and 2, that is to say, Figures 1 and 2, merely assist in indicating the precise relationship between the positions of the cylinders and the setting spindle for controlling the conduits between said cylinders. In other words, in the actual construction of shock absorber according to Figures 3, 5 and 6, the setting spindle is not disposed in a vertical plane containing the vertical axes of the cylinders, but is disposed to one side of said plane as represented in Figure 2. Figures 1 and 2, therefore, are included herein to simplify the drawings utilised in describing the invention, and to indicate that Figures 3, 5 and 6 are not true vertical sections through the vertical axes of the cylinders.

In the constructions according to the drawings the shock absorber casing I0 has a pair of cylinders I I, I2, and where road vehicles are concerned, said casing is adapted to be mounted rigidly on the chassis 8 of the vehicle, which constitutes one of the elements whose relative movement is to be damped. Pistons I3, I4 are connected by links I5, I6, respectively with a crank II which is mounted for rotation with a shaft I3 of the shock absorber which is connected by a link I9 either directly to or through further linkage with the other element of the pair to be damped, which in the case of a Vehicle may constitute one of the wheels on the wheel axle 2 (Fig. 7).

As in the constructions described in patent specifications Nos. 2,117,644, 2,117,645 and 2,117,646 and in my co-pending application Serial No. 289,623, filed May 23, 1938, of which this application is a division, communication is established between the cylinders II and I2 of the shock absorber through a conduit comprising passages 22, 2I and a longitudinal bore 22 in the casingof the shock absorber. In this bore is mounted a spindle 23 having a hollow and relatively narrow end 22 on which is seated a ball 25, loaded by a spring 26. A tapered annular ring 21 surrounds the extreme end of the hollow portion 22 of the spindle and is resiliently loaded by a spring 28; the part 24 is transversely bored at 29. Thus, on downward displacement of the piston I3 under normal circumstances, i. e. when a vehicle is travelling along a road without any inclination to tilt, and a wheel or wheels encounter an obstruction in the road, the pistons I3, I I, are displaced in their cylinders on displacement of the link I9 and the crank I! to cause fluid to pass between the cylinders II and I2. When the piston I3 descends on its compression stroke fluid is forced through the passage 2!) into the bore 22, through the bore 29 into the interior of the hollow end 24 of the spindle 23 and forces the ball 25 all its seat against the load created by the spring 26 whereby the fluid enters the passage 21 and thence into the cylinder I2.

On reverse displacement of the pistons I3, I l, that is to say on the upward stroke of the piston I3 and the downward stroke of the piston I4, the fluid leaves the cylinder I2, enters the passage 2| and being unable to open the ball valve, forces the tapered annulus 27 upwardly against its spring 28, so that the fluid enters the bore 22 and thus passes through the passage 20 into the cylinder II. As the ball valve 25 and the annulus 27 are unequally loaded, it will be seen that there is a differential resistance to fluid flow in opposite directions of piston displacement.

By the present invention additional means are provided to control the displacement of the pistons in the event of the vehicle tilting or tending to tilt and in the construction according to Figure 3, such means includes the provision of a setting spindle 30 which has transverse bores SI, 32, 33, formed therein. The transverse bore 3I in one position of angular displacement of the setting spindle 30 is adapted to open the passage 2 I. In another position of angular displacement of the spindle 32, a conduit 34 between the cylinders I I and I2 is opened by the transverse bore 32, whilst in a third position of angular displacement of the spindle 32 a third conduit 35 between the cylinders II and I2 is opened by the transverse bore 33 of the spindle. In other words, the transverse bores 3!, 32, 1-33 extend in different directions, radially of the spindle and when any one bore opens its conduit the other two conduits are closed. 7

Both the left hand end of the conduit 34 and the right hand end of the conduit 35 (Figure 3) have a tapered annulus 3t resiliently loaded by a relatively strong spring 3i and a ball valve 33 resiliently loaded by a relatively light spring 39. As a result when the conduit 3% is open at a predetermined angular position of the spindle 33 causing the bore 32 therein to lie co-axia-l or substantially co-axial with the conduit 32, fluid from the cylinder I I can enter the cylinder I2 on displacement of the pistons by raising the tapered annulus 35 off its seat against the relatively heavy load but on reverse direction of displacement of the pistons, fluid from the cylinder I2 can pass into the cylinder II by forcing the ball 38 against its relatively light load off its seat. Thus there is a greater resistance to downward movement of the piston I3 on. opening of the conduit 34 than exists on downward movement of the piston I I, whilst the opposite result takes place when the conduit 35 is opened, that is to say, a greater resistance is applied to the compression stroke of the piston I4 than to the piston l3.

As the angular displacement oi the spindle 38 can be controlled by a pendulum or inertia mass pivotally supported on the vehicle, it will be seen that whether the vehicle remains horizontal or in any predetermined position relatively to the wheels or is accompaniedby a tendency totilt or tilting, in either direction from said predetermined position, a difierential resistance to fluid flow is created.

Accordingly, should the vehicle tend to tilt in one direction such as for example, on cornering and the conduit 34 and the passages 20, 2i are closed leaving the conduit 35 open, the resistance to tilt is created by the valve 32, whilst should the vehicle meet an. obstruction in the road while cornering, the smaller the resistance to movement of the shock absorber parts due to such obstruction in the opposite direction is resisted by the spring loaded valve 38. In other words, not only does the shock absorber provide a resistance to displacement of the shock absorber parts under ordinary circumstances when the vehicle is travelling in a direct line along a road and meets an obstruction, which circumstances are controlled by the valves associated with the passage 20, 2I but in addition tilting or tendency to tilt in one direction is controlled by the heavily loaded valve of the conduit 34 and in the other direction by the heavily loaded valve in the conduit 35, whilst during said tilting or tendency to tilt, any displacement due to the vehicle meeting an obstruction in the road is resisted by the relatively lightly loaded valves 38 in the conduits 34, 35, according to whether the vehicle is taking a right hand or a left hand curve.

In the construction according to Figure 4 which shows a suitable form of mechanism for angularly rotating the spindle 30, a pendulum or inertia mass 40 is keyed to an oscillating valve 4| having passageways 42, 43, 44 therein. This oscillating valve 4| is adapted to establish communication between a vacuum tank 45 having a non-return valve 46 controlling its communication 41 with the induction pipe of the engine and either side 48, 49 of bellows 50 according to the position taken up by the valve 4|. The bellows has a partition 5| formed therein which has a link connection 52 with a lever 53 connected with the upper end of the spindle 30. As a result, when the pendulum or inertia mass 40 remains vertical the bellows 50 is isolated from the suction tank 45 leaving the partition disposed centrally of the bellows, in which case the bore 3| of the spindle opens the passage 2|. When, however, the pendulum 45 moves to one side due to tilting of the vehicle, one or other of the passages 42, 43 is adapted to establish connection with one side of the bellows to force this to the right or left as the case may be and thus angularly displace the lever 53 and the setting spindle 30 into such a position as tobring either the bore 32 co-axial with the conduit 34 or the bore 33 co-axial with the conduit 35.

In the modified form of construction illustrated in Figure 5 a longitudinally displaceable setting spindle 54 is substituted for the angularly displaceable setting spindle 30. Accordingly, the spindle is provided with three neck portions 55, 55 and 51, which, in accordance with the degree of longitudinal displacement of the spindle is adapted to open either the passage 2|, the conduit 34 or the conduit 35.

In the construction according to Figure 5, the upper end of the spindle is connected by a rod 58 with the partition 59 of a bellows 6|], the partition being displaceable according to whether a passage Gl or a passage 62 to the bellows on opposite sides of the partition 59 are placed in communication by an oscillating valve of the type shown in Figure 4 with the suction tank 45.

A similar type of longitudinally displaceable setting spindle is shown in the construction according to Figure 6, but in this case the pendulum or inertia mass is adapted to control the circuit of a pair of field windings 63, 64, of a solenoid 55, the armature 66 of which is connected by a rod 58 with the setting spindle 54.

For this purpose the field winding 63 lies in a circuit containing a battery 93 and a switch 92, whilst the field winding 64 lies in the circuit of the battery and a switch 9|. The pendulum 40 is adapted to swing about a horizontal pivot 94 extending longitudinally of the vehicle body and at a position preferably centrally of the width of the body, 1. e. remote from the shock absorber. This pendulum carries a pair of contacts 90 both of which are out of engagement with the contacts 9|, 92 so long as the pendulum remains vertical, i. e. so long as the vehicle body remains horizontal during travel. In this position of the pendulum, the armature 66 is maintained centrally of the solenoid under the control of springs 61, 68, and the field windings 64 are de-energised.

When, however, the vehicle tends to tilt in either direction one or the other of the windings 63, 64 is energised to attract the armature 66 and thus displace the setting spindle 54 to its required position for opening the required conduit 34 or 35.

In Figure '7 of the accompanying drawings, the various parts of the shock absorber system are shown in their relation to a vehicle chassis B and the wheel axle 9 which constitute the elements whose relative displacement is to be damped. Thus, the inertia mass 40, the valve 4|, the vacuum tank 45- and the bellows 50 are shown mounted in relation to the shock absorber.

It is to be clearly understood that various changes in the details of construction and. arrangement of parts may be made without departing from the scope of the invention as set forth in the appended claims.

I declare that what I claim is:-

1.' The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and each of the others is available to fluid flow according to the direction of tilt from said angle of one element relatively to the other, and means 35' common to all passages for closing two at a time.

2. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and each of the others is available to fluid flow according to the direction of tilt, one element relatively to the other, means common to all passages for closing two at a time, and means in each of said conduits for obtaining a differential resistance to fluid flow in opposite directions therein,

3. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and the other two are available to fluid flow according to the direction of tilt of one element relatively to the other, the resistance to fluid flow in one direction through each of said other two conduits on tilting in the outward direction from the predetermined angle being greater than on reverse tilting in the direction of return to said predetermined angle.

4. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be clamped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within whichsaid pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and the other two conduits are available to fluid flow according to the direction of tilt or tendency to tilt of one element relatively to the other, means common to all conduits for leaving one conduit only open at any time and inertia mass means adapted for displacement under the action of centrifugal force for displacing said common means.

5. The combination with a vehicle having a pair of relatively displaceable elements, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped and including a bore, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and the others are available to fluid flow according tothe direction of tilt of one element relatively to the other, a, longitudinally displaceable spindle in the bore of said casing having longitudinally spaced lateral passages adapted to register with all three conduits to leave one conduit only at any time available to fluid flow irrespective of the degree of longitudinal displacement of said spindle, inertia mass means located on the vehicle remote from the damping means for displacing said spindle, and means for interconnecting said inertia mass and said spindle for communicating displacement of one to the other.

6. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains horizontal or at a predetermined angle to the other element, and .the others are available to fluid flow according to the direction of tilt 01 one element relatively to the other, a spindle having relatively inclined radial bores at longitudinally spaced parts, equal to the spacing apart of the conduits, and inertia mass means for rotating said spindle about its axis to isolate at any time two of said conduits in maintaining fluid flow between said chambers through the third conduit only.

'7. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements comprising a casing adapted to be connected to one of the pair of elements whose relative displacement is to be damped, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, three conduits between said chambers, one of which is available to fluid flow when one of the two elements to be damped remains at a predetermined angle to the other element, and the others are available to fluid flow according to the direction of tilt of one element relatively to the other, a spindle having bores at longitudinally spaced parts unequal to the spacing apart of the conduits, and inertia mass means to displace said spindle longitudinally of its axis to isolate at any time two conduits to leave one conduit only available for maintaining fluid flow between said chambers.

8. The combination with a pair of relatively displaceable elements on a vehicle, of means for damping the relative displacement of said elements, comprising a casing adapted to be connected to one pair of elements whose relative displacement is to be damped, said casing having a bore therethrough, a shaft connected to the other element of said pair, a pair of pistons displaceable by said shaft, a pair of piston chambers within which said pistons are displaceable, a plurality of conduits between said chambers one of which is available to fluid flow when one of the two elements to be damped remains horizontal or at a predetermined angle to the other element and another being available to fluid flow according to the direction of tilt or tendency to tilt of one element relative to the other and a longitudinally displaceable spindle in the bore of said casing having longitudinally spaced lateral passages adapted to register with said conduits to leave one conduit only at a time available to fluid flow irrespective of the degree of longitudinal displacement of said spindle.

FULLERTON GEORGE GORDON ARMSTRONG. 

